and then you can skip the whole blockchain and use IPFS directly. NFTs do absolutely nothing for this use-case. They're merely a security hole that is plugged by something else off-chain.

In reality, an implementation that authenticates footage would use classic public-key cryptography with a private key embedded in a HSM in the camera, signing the output. You can't make it trustless with blockchain software, because necessarily the chain of trust has to end on the hardware (the hardware can be verified in theory, but blockchain is irrelevant for this, sinec there's no double-spend protection needed in this security model).